In the next generation communication system, also known as the 4th Generation (4G) communication system, researches are actively in progress to provide various services with Quality of Service (QoS) to users at a data transfer speed of approximately 100 megabit per second (Mbps). In particular, the 4 G communication system is currently being developed to ensure mobility and QoS in a Broadband Wireless Access (BWA) communication system, such as a Wireless Local Area Network (WLAN) system and a Wireless Metropolitan Area Network (WMAN) system. For this reason, Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) schemes are receiving attention as signaling of a physical channel.
A precoding scheme may be applied to increase capacity of an OFDMA system. When applying the precoding scheme, a precoding matrix varies on a block basis in a frequency domain. The precoding matrix is multiplied to perform suitable precoding according to a downlink channel experienced by each user or according to a frequency band variation of the channel. Because a user-specific pilot is precoded together with data, 2-dimensional Wiener-type channel estimation using only pilots in a specific block is applied rather than channel estimation used under the premise of the conventionally used cell-specific pilot. Herein, the user-specific pilot may also be referred to as a dedicated reference signal, and the cell-specific pilot may also be referred to as a common pilot.
In the 2-dimensional Wiener-type channel estimation, increasing the block size, may result in better the performance but also adds more complexity. Therefore, it is difficult to implement a Wiener-type channel estimator for a block that includes a specific size or larger. Accordingly, if the block size is large, instead of the 2-dimensional Wiener-type channel estimation, Finite Impulse Response (FIR) filtering/Infinite Impulse Response (IIR) filtering-based channel estimation, which is simple but excellent in capability, may be preferred.
Implementation of both of the Wiener-type channel estimation and the FIR filter/IIR filtering-based channel estimation results in increase of hardware complexity and overhead of controlling in the receiving end. Therefore, there is a need for a method of implementing the Wiener-type channel estimation and the FIR filter/IIR filtering-based channel estimation without increasing the hardware complexity and the overhead of controlling.